Membranes, particularly nanoporous membranes, are known to have applications in a number of areas including filtration of biological fluids, removal of micropollutants, water softening, wastewater treatment, retention of dyes, preparation of ultrapure water in the electronics industry, and concentration of food, juice, or milk. Methods involving block copolymers, which self-assemble into nanostructures, have been proposed for preparing nanoporous membranes. While self-assembled structures are advantageous in that they produce membranes with uniform pore size and pore size distribution, challenges or difficulties remain with the proposed block copolymers and methods. For example, in some of these methods, a film is produced first from a block copolymer, which is then followed by the removal of one of the blocks of the block copolymer by employing a harsh chemical such as a strong acid or strong base.
The foregoing indicates that there is an unmet need for membranes made from block copolymers that are capable of self-assembling into nanostructures and for a method for producing nanoporous membranes from these block copolymers, which does not require a removal of one of the blocks after a nanostructure is formed.